An exemplary device for separating paramagnetic materials (the first particles) such as hematite Fe2O3, ilmenite FeTiO3 or pyrrhotite having positive magnetic susceptibility from mixture comprising the first particles and less magnetic second particles is shown in FIGS. 1a-c. In these figures, the first particles are presented as white circles one of which is denoted with a reference number 113 and the second particles are presented as black circles one of which is denoted with a reference number 114. The device includes magnetizing equipment 101 for producing magnetic field acting on the mixture, carrier equipment 102 for carrying the mixture so that the mixture is adapted to move with respect to the magnetic field. The magnetizing equipment and the carrier equipment are adapted to produce the magnetic field and to carry the mixture, respectively, so that mutually opposite polarity portions of the magnetic field are adapted to sweep the mixture in a sweeping direction and thereby deflect the direction of movement of the first particles towards the sweeping direction and away from the direction of movement of the second particles so that the deflected direction of movement of the first particles intersects the sweeping direction. The deflected direction of movement of the first particles makes it possible to receive the first and second particles with separate collectors 131-133. As each particle of the mixture can be repetitively swept by the portions of the magnetic field having the mutually opposite polarities, the magnetic force caused by the sweeping is directed to each of the particles many times.
In the exemplifying device illustrated in FIGS. 1a-c, the carrier equipment 102 comprises a conveyor belt 109 driven with an electrical motor 119. The longitudinal direction of the conveyor belt 109 is substantially parallel with a rotation axis of each of the rotating elements 103-106 driven with electrical motors 122 and 123. The conveyor belt is adapted to receive the mixture 112 from a feed box 120 and to move the mixture so that the mixture is a distance away from magnetizing equipment producing the magnetic field. The direction of the movement of the conveyor belt 109 is depicted with an arrow 130 in FIG. 1b. 
An enlargement of the feed box of the device of FIGS. 1a and 1b is shown in FIG. 1c. As seen from the FIG. 1c, the first and the second particles are randomly distributed in the mixture 112. When the particles are allowed to fall from the feed box 120 to the conveyor belt 109, they give rise to a randomly organized mixture wherein some of the first particles are on the top of the mixture while some other of the first particles are in the bottom of the mixture. If the first particles to be separated are heavier than the second particles, they are prone to fall at the bottom of the mixture.
As seen from FIG. 1b, the first and second particles start to separate only after reaching the magnetizing equipments 103 and 104. Accordingly, their separation may be challenging especially when high speed of the conveyor belt and relatively weak magnetic fields are used, and when a mixture comprising plurality of particles of different magnetic susceptibility need to be separated. Thus there is a need for making their separation more effective.
US 2013/016240A1 discloses a device and a method for separating non-ferrous material. The document teaches separating any ferrous material present by using eddy current, and further separation of weakly magnetic material on a device equipped with a slowly running conveyor belt and slowly rotating discs comprising plurality of permanent magnets.
US 2012/279906A1 discloses a magnetic roller type separating device comprising neodymium magnets. The device is suitable for ore concentration.
U.S. Pat. No. 1,729,589 discloses a device and method for separation and concentration of minerals of an ore. The device comprises a feed box for the ore, and plurality of electro-magnets for deflecting the direction of movement of the ore particles based on their magnetic susceptibility. The magnets are located either below the feed box or below a non-magnetic launder.
U.S. Pat. No. 4,659,457 discloses an ore separator for concentrating magnetic or weakly magnetic minerals having a relatively high specific gravity. The separator utilizes codirectional magnetic and gravitational forces to achieve separation.
U.S. Pat. No. 6,041,942 discloses an apparatus for magnetically separating cracking catalysts comprising a flexible continuous woven aromatic polyamide fiber belt movable around first and second rollers opposite ends thereof for receiving a catalyst stream on an upper surface thereof, wherein one of the rollers comprise a plurality of stacked radial magnetic discs with poles facing each other to provide a concentrated magnetic field to influence particles in the catalyst stream having magnetic properties.